Thanks for the info. Totally your call, if you think it's informative to post anything. I enjoy the articles I read on TrackMan, so I'd be at least one very interested person on the topic. I find it all fascinating and it enhances the feel I'm slowly developing in my swing. Knowledge based on data (if it's good data) can enhance what we sense on the course and the range. I was one of those taught erroneously many many years ago about lining up in the direction of where you want the ball to start and point the club face to where you want the ball to end up... and it led to frustration I still remember. As I get into golf again after a years-long break, I'm glad to see technology put to use in a way that can help us be armed with better knowledge of the ball flights/swing contact.

1. How much curve can gear effect impart on an iron shot? Especially where the iron in question is a "players cavity" or a blade, rather than a deep-cavity model? I have always been under the impression that, at least with blades, you would not see a toe hit curve left, or a heel shot turn right.

2. Even with a driver, heel and toe strikes will much more obviously curve - but they should not land offline if clubface bulge works as intended. For example, assuming a square face and path, a toe strike should (according to theory) start right and curve back to the middle, but not hook into the left rough. How does this work out in practice? Is bulge actually working to the extent intended, or can it only ameliorate some of the adverse gear effect curve?

Obviously, in both cases, irons and drives, any off-centre impact will result in a drop in ball speed and carry.

1. How much curve can gear effect impart on an iron shot? Especially where the iron in question is a "players cavity" or a blade, rather than a deep-cavity model? I have always been under the impression that, at least with blades, you would not see a toe hit curve left, or a heel shot turn right.

2. Even with a driver, heel and toe strikes will much more obviously curve - but they should not land offline if clubface bulge works as intended. For example, assuming a square face and path, a toe strike should (according to theory) start right and curve back to the middle, but not hook into the left rough. How does this work out in practice? Is bulge actually working to the extent intended, or can it only ameliorate some of the adverse gear effect curve?

Obviously, in both cases, irons and drives, any off-centre impact will result in a drop in ball speed and carry.

All depends on the severity of the miss (i.e location). Yes you can still get gear effect curve even with player's irons. It's not severe but you have a face open to the path and still negative spin axis ( draw).

Bulge does help lessen the effect but the starting direction of the ball's flight and the amount of curve or axis tilt depends on how much face deflection occurred and what the actual face angle is at max compression.